Liver transplantation is the only curative treatment for end-stage liver disease, acute liver failure and selected patients with liver cancer. Every year, more than 20,000 liver transplantations are performed worldwide and this activity is concentrated in the Western world using cadaveric organ donors.
A rare but potentially fatal complication after liver transplantation is PNF. PNF is defined as the absence of initial function following transplantation. Such evidence would include not only frank signs of total hepatic failure (e.g., profound hypoglycemia, uncorrectable coagulopathy, stage IV coma, renal failure, acidosis, and cardiodynamic shock), but also other signs of irreparable damage to the organ (i.e., massive rises in transaminases along with unrelenting daily rises in bilirubin, persistent renal insufficiency, mental confusion and persistent coagulopathy). The only treatment is an urgent retransplantation within 24-48 hours.1 The incidence of PNF ranges from 2% to 10% and is responsible for 36% of retransplantation. PNF is associated with a female recipient, steatosis of the donor liver graft and an increased cold ischemia time.2 
Thus, there is a need to predict the occurrence of PNF based on assessing the quality of the donor liver.
The current strategy for donor organ “selection” is based on a clinical assessment of the donor organ using clinical parameters including age, sex, race, comorbidity, cause of death, biochemical values (liver enzymes), allocation and donor type and ischemia time. Based on these parameters, a Donor Risk Index3 has been developed, with an adaptation for the Eurotransplant region (the Eurotransplant DRI (ET-DRI)),4 that provides an estimation of possible graft dysfunction, but not a formal assessment of graft quality. Moreover, DRI is often not predictive of PNF.
Biomarkers for viability have been studied in liver tissue (necessitating a liver biopsy) or perfusate. Perfusate samples are easy to collect and, in contrast to a liver biopsy that only represents a small part of the liver, represent the global liver function. In this regard, perfusate has been studied for decades in order to predict organ failure after liver transplantation. Previous reports propose AST, a routinely used liver enzyme, as a marker for graft viability.5 However, sensitivity and specificity are insufficient. Other authors reported hyaluronic acid in perfusate as a marker for PNF, with a high negative predictive value for the appearance of PNF.6 Other experimental biomarkers in perfusate have been proposed using HDmiR, hepatocyte-derived miRNA, but are focused on other outcome parameters than PNF.7 
A new strategy to increase the quality of donor organs is the use of machine perfusion rather than cold storage. During transport, the organ vessels are perfused actively, which could improve outcome of the organ and also increase the donor organ pool.8 However, the use of machine perfusion increases the need for reliable biomarkers to assess organ viability during and after perfusion.
In addition to the use of machine perfusion, a decreasing organ quality and an increasing demand for liver transplantation necessitate a search for a robust biomarker for liver graft quality.
The glycome is defined as the mixture of carbohydrate structures present in a biological sample. When these glycan structures are linked to an asparagine residue of proteins, it is defined as the N-glycome. In the early years of 2000, Callewaert et al.9 developed a platform for high-throughput and high-sensitivity quantitative profiling of the N-glycome, using a DNA fragment analysis equipment (common in molecular genetics laboratories). This technique was successfully applied to analyze the serum N-glycome and led to the development of biomarkers for liver cirrhosis (GlycoCirrhoTest),10 liver fibrosis (GlycoFibroTest),11 and non alcoholic steatohepatitis (GlycoNashTest).12, 13 
Verhelst et al.14 further disclosed glycomics as a tool for preservation fluid analysis in liver transplantation. These authors demonstrate that electropherograms or N-glycome profiles of liver perfusate before engraftment show an important similarity with electropherograms or N-glycome profiles of serum of healthy human volunteers.
Verhoeven et al.7 disclose that PNF of liver graft during machine preservation can be assessed by determining the degree of graft steatosis. Blomme et al.12 disclose that glycan-based biomarkers can be used to measure the presence and degree of lobular inflammation in patients with non-alcoholic steatohepatitis (NASH). However, the latter biomarker is clearly not a marker of the presence of steatosis as is confirmed by the data presented in this disclosure. Moreover, the latter authors determined that N-glycans is in the serum—not in perfusate—of non-alcoholic fatty liver disease patients.
Taken together, the existence of a robust and reliable glycomarker, which can be used to predict PNF, has not been described nor suggested.